Pistons specs question for 340 build
Read this from Summit. It clearly states how to measure a dish and dome. Dish=positive number dome=negative number.
Piston Head Volume
It also states that those figures are not standard across the industry. Neither is intelligence.
That means to get the math RIGHT you MUST USE a positive number for any dishes or valve reliefs and a negative number for any domes or protrusions into the chamber, or your math WILL BE WRONG.
Just because someone uses one particular way to state a measurement doesn't make it right, I don't give a damn who it is.
So be damned careful when you measure volume, because it's easy to get wrong, especially with stupid people giving incorrect measurements for their products.